Disclosed are a key configuration method, apparatus and system. The method comprises: a policy function network element receiving a request for communication between a user equipment and a network device; based on the request, UE registration information, subscription service data and service security requirements, determining a user plane protection mechanism; when the network device is a CN device, the policy function network element sending the user plane protection mechanism to an algorithm network element; the algorithm network element determining, based on the user plane protection mechanism, a security protection algorithm, generating, based on the security protection algorithm, a first user plane protection key, sending the first user plane protection key to the CN device and sending the security protection algorithm to the user equipment; and the user equipment generating, based on the security protection algorithm, a second user plane protection key. The embodiments of the present invention can realise the respective and complete configuration of a user plane protection key by a user equipment and a network device during 5G communication, thus improving the security of user plane data transmission and realising network security protection.